The 2012 report, “Review of California’s Water Recycling Criteria for Agricultural Irrigation,” was developed in response to increased interest in expanding the amount of recycled water used for agricultural purposes.
- It specifically addressed the risk of exposure and infection from waterborne pathogens, such as Cryptosporidium and E. coli, due to the irrigation of a wide variety of food crops using recycled water.
Key issues addressed include:
- Characterizing “safe” recycled water for use in irrigation.
- Appropriate assumptions regarding an acceptable risk to public health.
- Relevancy of current criteria for reducing viruses and using chlorine disinfection.
- Need for a “multiple barrier” of treatment processes to remove microorganisms.
- Use of turbidity as a valid parameter to assess the performance of treatment processes.
- Standards used to clarify and define “secondary wastewater treatment,” which involves biological treatment processes to remove contaminants and/or bacteria.
- Use of total coliform bacteria to assess the effectiveness of disinfection in reducing microorganisms.
- Ability of crops to take in viruses through their root systems, leaves, and other points of entry, and any associated risks to public health.